Chunks of poached salmon,tender potatoes, and crispharicots verts are the baseof this zesty salad topped withtangy horseradish dressing.
Place potatoes in a large saucepan; fill with cold water. Add 1 tablespoon salt; bring to a boil. Reduce to a simmer; cook until fork tender, 30 to 35 minutes. Remove from heat. Drain; set aside.
Fill a large bowl with ice and water; set aside. Rinse saucepan; fill with cold water. Bring to a rolling boil. Add remaining 1/2 tablespoon salt and beans; cook until bright green and tender, about 5 minutes. Remove from heat. Drain; plunge into ice bath. Drain; pat dry.
Combine vinegar and horseradish in a small bowl. Whisk in olive oil; season with salt and pepper.
Halve potatoes and beans; place in a bowl. Add red onion and chives and half of the dressing; toss gently. Divide vegetables among four plates. Slice salmon into fork-size pieces. Place salmon on top of vegetables; drizzle with remaining dressing. Serve with greens if desired.